docs: def only(self, *args, **kwargs):
          """
          Override default implementation to ensure that we *always* include the
          `publishing_is_draft` field when `only` is invoked, to avoid eternal
          recursion errors if `only` is called then we check for this item
          attribute in our custom `iterator`.
  
          Discovered the need for this by tracking down an eternal recursion
          error in the `only` query performed in
          fluent_pages.urlresolvers._get_pages_of_type
          """
          field_names = args
          if 'publishing_is_draft' not in field_names:
              field_names += ('publishing_is_draft',)
          return super(PublishingQuerySet, self) \
              .only(*field_names, **kwargs)